Pioglitazone raises bladder cancer risk in diabetes patients

Patients with type 2 diabetes who take medication pioglitazone have a higher risk of incident bladder cancer than diabetes patients who do not, researchers from McGill University, Canada, reported in the BMJ. The authors added that bladder cancer risk was also linked to pioglitazone usage duration and dosage. The team set out to find out whether pioglitazone usage might raise the risk of incident bladder cancer among type 2 diabetes patients. They conducted a retrospective cohort study and used a nested case-control analysis. This involved gathering and examining data from over 60 GP (general practitioner, primary care physician) centers in Great Britain. Patients on pioglitazone were compared to individuals newly treated with oral hypoglycaemic agents between 1 January 1988 and 31 December 2009 - all individuals in both groups had diabetes type 2. They found that ever use of pioglitazone was linked to a higher risk of developing bladder cancer (rate ratio 1.83, 95% confidence interval 1.10 to 3.05). They added that cancer bladder risk went in line with pioglitazone use duration - the longer patients were on pioglitazone, the higher their risk of bladder cancer. Highest bladder cancer risk was found among those who had been on pioglitazone for over two years. Patients on cumulative dosage of over 28,000 mg also had a higher risk, than those on lower dosages.